This card, if not for the crease could have easily scored and 8/8.5 (a potential dollar value of around $2000) with the majority of surface and edge damage having been caused by the folding
Pokmon TCG Pocket, meanwhile, looks like a great fresh start
So the math only works at the top of the value range

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For example, a card with 9/9/10/10 will have a grade of 9
Unlike mana, which you can't keep for very long if you don't spend it, energy counters stay with you turn after turn until you spend them or an effect causes you to lose them